Laptop computers include densely packed circuitry, high density hard drives, and internal other components, all of which generate heat during operation of the computer. Because this heat is not useful for the operation of the computer, it can be considered to be waste heat. Many cooling mechanisms are available to remove or dissipate waste heat from the computer, or to mitigate the effects of waste heat on the operation of the computer components. Such cooling mechanisms include fans, heat pipes, heat sinks, and thermal spreaders. These cooling mechanisms can remove heat generally from the entire computer casing, or can be specially designed to remove heat from particular components, including the CPU, GPU, power supply, and hard drive. As long as these components are kept below their thermal rating for operation, the computer functions properly.
However, because the components of the computer often have thermal ratings well above ambient temperature (i.e., higher than about 70 degrees Fahrenheit), residual waste heat not removed by the cooling mechanisms is often transferred to the user via radiation, convection, and conduction from the heat generating components to the casing of the computer, and then usually by conduction or convention to the lap and/or hands of the user, thereby causing discomfort to a user.
Prior attempts to mitigate the discomfort of a user from residual waste heat being transferred to the user's lap from the bottom of the computer casing have involved providing a mechanism for circulating air between the bottom of the computer casing and the lap of a user, and such attempts have often required fans or other active components.